JPH0115208B2 - - Google Patents
Info
- Publication number
- JPH0115208B2 JPH0115208B2 JP11444882A JP11444882A JPH0115208B2 JP H0115208 B2 JPH0115208 B2 JP H0115208B2 JP 11444882 A JP11444882 A JP 11444882A JP 11444882 A JP11444882 A JP 11444882A JP H0115208 B2 JPH0115208 B2 JP H0115208B2
- Authority
- JP
- Japan
- Prior art keywords
- zinc oxide
- oxide thin
- thin film
- vibrator
- electrode
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical class [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims description 76
- 239000011787 zinc oxide Substances 0.000 claims description 38
- 239000010409 thin film Substances 0.000 claims description 37
- 239000000758 substrate Substances 0.000 description 6
- 238000010586 diagram Methods 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 230000010355 oscillation Effects 0.000 description 3
- 238000004544 sputter deposition Methods 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 238000005452 bending Methods 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 238000010894 electron beam technology Methods 0.000 description 2
- 230000001747 exhibiting effect Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 230000002123 temporal effect Effects 0.000 description 2
- 238000007740 vapor deposition Methods 0.000 description 2
- 230000003321 amplification Effects 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 229910052681 coesite Inorganic materials 0.000 description 1
- 229910052906 cristobalite Inorganic materials 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005566 electron beam evaporation Methods 0.000 description 1
- 238000007733 ion plating Methods 0.000 description 1
- 238000010884 ion-beam technique Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 229910052682 stishovite Inorganic materials 0.000 description 1
- 238000010897 surface acoustic wave method Methods 0.000 description 1
- 229910052905 tridymite Inorganic materials 0.000 description 1
- 238000007738 vacuum evaporation Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/125—Driving means, e.g. electrodes, coils
- H03H9/13—Driving means, e.g. electrodes, coils for networks consisting of piezoelectric or electrostrictive materials
- H03H9/131—Driving means, e.g. electrodes, coils for networks consisting of piezoelectric or electrostrictive materials consisting of a multilayered structure
Description
【発明の詳細な説明】
この発明は安定な特性を示す酸化亜鉛薄膜の電
極構造に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrode structure of a zinc oxide thin film exhibiting stable characteristics.
酸化亜鉛薄膜は弾性表面波装置、音叉振動子、
音片振動子などの圧電体として使用されている。
この酸化亜鉛薄膜の使用例を音叉振動子にもとづ
いて説明する。 Zinc oxide thin film is used in surface acoustic wave devices, tuning fork vibrators,
It is used as a piezoelectric material such as a vibrator.
An example of the use of this zinc oxide thin film will be explained based on a tuning fork vibrator.
第１図は音叉振動子の一例を示す側面図であ
る。 FIG. 1 is a side view showing an example of a tuning fork vibrator.
図において、１は音叉振動子の本体、２，３は
この本体１の脚部を示し、脚部２，３の側壁２
ａ，３ａには酸化亜鉛薄膜４，５が形成されてい
る。この酸化亜鉛薄膜４，５は真空蒸着法、スパ
ツタリング法、イオンプレーテイング法などによ
り形成される。６，７は酸化亜鉛薄膜４，５の上
に形成されたAl電極を示す。 In the figure, 1 indicates the main body of the tuning fork vibrator, 2 and 3 indicate the legs of this main body 1, and side walls 2 of the legs 2 and 3.
Zinc oxide thin films 4 and 5 are formed on a and 3a. The zinc oxide thin films 4 and 5 are formed by vacuum evaporation, sputtering, ion plating, or the like. 6 and 7 indicate Al electrodes formed on the zinc oxide thin films 4 and 5.
このAl電極６，７は安価でボンデイングがで
きることから選ばれたもので、電子ビーム蒸着法
などにより3000〜10000Åの膜厚の範囲で形成さ
れる。 The Al electrodes 6 and 7 were selected because they are inexpensive and can be bonded, and are formed to a thickness of 3,000 to 10,000 Å by electron beam evaporation or the like.
しかしながら、上記したような酸化亜鉛薄膜の
電極構造では次のような欠点が見られる。つま
り、Al電極そのものが高い親和性を示すため、
酸化亜鉛薄膜中にAlが拡散し、電気的特性が劣
化するという欠点がある。すなわち、２価の半導
体である酸化亜鉛に３価であるAlが拡散するこ
とによつて酸化亜鉛薄膜の電気的特性、たとえば
振動周波数を大きく変化させるという現象が認め
られた。また高温負荷寿命試験を行うと、さらに
上記した現象が促進され、電気的特性の劣化が一
層大きなものとなつた。 However, the electrode structure of the zinc oxide thin film as described above has the following drawbacks. In other words, since the Al electrode itself shows high affinity,
The drawback is that Al diffuses into the zinc oxide thin film, deteriorating the electrical properties. That is, a phenomenon has been observed in which the electrical properties of the zinc oxide thin film, such as the vibration frequency, are significantly changed due to the diffusion of trivalent Al into zinc oxide, which is a divalent semiconductor. Furthermore, when a high-temperature load life test was conducted, the above-mentioned phenomenon was further accelerated, and the deterioration of the electrical characteristics became even more significant.
したがつて、酸化亜鉛薄膜を形成するに当つて
は、電極を含めた構成全体について考慮する必要
があり、従来の電極構成にさらに改良を施さなけ
ればならなかつた。 Therefore, when forming a zinc oxide thin film, it is necessary to consider the entire structure including the electrode, and it is necessary to further improve the conventional electrode structure.
この発明はかかる背景からなされたものであ
り、安定な特性を示す酸化亜鉛薄膜の電極構造を
堤供することを目的とする。 The present invention was made against this background, and an object of the present invention is to provide an electrode structure of a zinc oxide thin film exhibiting stable characteristics.
以下この発明を実施例にもとづいて詳細に説明
する。 The present invention will be described in detail below based on examples.
第２図はこの発明にかかる酸化亜鉛薄膜の電極
構造を音叉振動子に適用した例を示す側面図であ
る。 FIG. 2 is a side view showing an example in which the zinc oxide thin film electrode structure according to the present invention is applied to a tuning fork vibrator.
１１はエリンバなどからなる金属音叉、１２は
酸化亜鉛薄膜、１３はＶ層、１４は電極である。
このうちＶ層１３は電子ビーム法、スパツタリン
グ法、イオンビーム法、抵抗加熱蒸着法などによ
つて形成される。 11 is a metal tuning fork made of Erimba or the like, 12 is a zinc oxide thin film, 13 is a V layer, and 14 is an electrode.
Among these, the V layer 13 is formed by an electron beam method, a sputtering method, an ion beam method, a resistance heating vapor deposition method, or the like.
第３図は屈曲振動モードの音片振動子にこの発
明にかかる酸化亜鉛薄膜の電極構造を適用した例
を示した斜視図である。 FIG. 3 is a perspective view showing an example in which the electrode structure of the zinc oxide thin film according to the present invention is applied to a sound element vibrator in a bending vibration mode.
図において、２１は振動子本体を示し、振動子
２２とこれを支持部２４で支持している枠体２３
から構成されている。２５は酸化亜鉛薄膜で振動
子２２の表面に形成されている。２６は酸化亜鉛
薄膜２５の上に形成されたＶ層、２７はＶ層２６
の上に形成されたAl電極である。 In the figure, reference numeral 21 indicates a vibrator main body, which includes a vibrator 22 and a frame body 23 that supports the vibrator 22 with a support section 24.
It consists of 25 is a zinc oxide thin film formed on the surface of the vibrator 22. 26 is a V layer formed on the zinc oxide thin film 25, 27 is a V layer 26
This is an Al electrode formed on top of the .
第４図は同じくこの発明を他の屈曲振動モード
の振動子に適用した例の側面図である。 FIG. 4 is a side view of an example in which the present invention is applied to another bending vibration mode vibrator.
図において、３１はセラミクス、プラスチツ
ク、ゴムなどの基板、この基板３１表面には、
Al電極３２、Ｖ層３３、酸化亜鉛薄膜３４、Ｖ
層３５、およびAl電極３６が順次形成されてい
る。 In the figure, 31 is a substrate made of ceramics, plastic, rubber, etc. On the surface of this substrate 31,
Al electrode 32, V layer 33, zinc oxide thin film 34, V
A layer 35 and an Al electrode 36 are sequentially formed.
第５図は同じくこの発明を拡がり振動モードの
振動子に適用した例を示す側面図である。 FIG. 5 is a side view showing an example in which the present invention is applied to a vibrator in a spread vibration mode.
図において、４１は酸化亜鉛薄膜、４２は酸化
亜鉛薄膜４１の両面に形成されたＶ層、４３はＶ
層４２の上に形成されたAl電極である。 In the figure, 41 is a zinc oxide thin film, 42 is a V layer formed on both sides of the zinc oxide thin film 41, and 43 is a V layer.
This is an Al electrode formed on layer 42.
第６図は同じくこの発明を厚み振動モードの振
動子に適用した例を示す側面図である。 FIG. 6 is a side view showing an example in which the present invention is applied to a thickness vibration mode vibrator.
図において、５１はSi、SiO2などからなる基
板、基板５１の上にはAl電極５２、Ｖ層５３が
順次形成されている。さらにＶ層５３の上には酸
化亜鉛薄膜５４が形成されている。この酸化亜鉛
薄膜５４が形成されている位置に相当する基板５
１には空部５１ａが形成されている。酸化亜鉛薄
膜５４の上にはＶ層５５、およびAl電極５６が
順次積層して形成されている。 In the figure, reference numeral 51 denotes a substrate made of Si, SiO2, etc., and an Al electrode 52 and a V layer 53 are formed in this order on the substrate 51. Furthermore, a zinc oxide thin film 54 is formed on the V layer 53. Substrate 5 corresponding to the position where this zinc oxide thin film 54 is formed
1 has a hollow portion 51a formed therein. A V layer 55 and an Al electrode 56 are sequentially laminated on the zinc oxide thin film 54.
次に具体的な実施例として、第２図に示した音
叉振動子についてこの発明にかかる酸化亜鉛薄膜
の電極構造を適用した例を説明する。 Next, as a specific example, an example in which the electrode structure of the zinc oxide thin film according to the present invention is applied to the tuning fork vibrator shown in FIG. 2 will be described.
第２図を参照して説明すれば、振動子１１の上
にスパツタリング法により酸化亜鉛薄膜１２を形
成し、その上にＶを層１３を抵抗加熱蒸着法によ
り430Åの厚みに形成し、さらにその上に厚みが
1μからなるAl電極１４を電子ビーム法により形
成した。このようにして振動周波数32KHzの振動
子を作成した。 Referring to FIG. 2, a zinc oxide thin film 12 is formed on the vibrator 11 by sputtering, a V layer 13 is formed on it to a thickness of 430 Å by resistance heating vapor deposition, and then thickness on top
An Al electrode 14 having a thickness of 1 μm was formed by an electron beam method. In this way, a vibrator with a vibration frequency of 32KHz was created.
この振動子に直流電圧20Vを印加し、120℃の
温度に10000時間放置した。このときの振動周波
数の経時変化特性を試料数20個について測定した
ところ第７図に示すような結果が得られた。図中
実線はこの実施例によるものである。また破線は
従来例のAl電極のみからなるものについて、同
様にして測定した結果を示したものである。この
振動周波数の経時変化特性（ΔF／Fo）は次式よ
り求めた。 A DC voltage of 20V was applied to this vibrator, and it was left at a temperature of 120°C for 10,000 hours. When the temporal change characteristics of the vibration frequency at this time were measured for 20 samples, the results shown in FIG. 7 were obtained. The solid line in the figure is based on this embodiment. Moreover, the broken line shows the results of measurements made in the same manner for a conventional example made of only Al electrodes. The temporal change characteristic (ΔF/Fo) of this vibration frequency was determined from the following equation.
ΔF／Fo＝振動周波数の経時変化値−振
動周波数の初期値／振動周波数の初期値（ppm）
また、直列共振抵抗（Ro）についても同様に
測定し、その結果を第８図にそれぞれ示した。 ΔF/Fo = Change value of vibration frequency over time - Initial value of vibration frequency / Initial value of vibration frequency (ppm) Series resonant resistance (Ro) was also measured in the same way, and the results are shown in Figure 8. .
第７図〜第８図から明らかなように、この発明
にかかるものは、従来例にくらべて、振動周波数
の経時変化が小さく、またRoの経時変化が小さ
くかつその値も小さいなどの効果が得られてい
る。 As is clear from FIGS. 7 and 8, the device according to the present invention has effects such as a smaller change in vibration frequency over time and a smaller change in Ro over time than the conventional example. It has been obtained.
ここで、Roを測定したのは次のような理由に
よる。 The reason why Ro was measured here is as follows.
まず、酸化亜鉛薄膜についてその等価回路を示
せば第９図のようになる。図中、Cdは並列容量
を示し、酸化亜鉛薄膜をコンデンサとして考えた
場合の静電容量に近い値である。Roは直列共振
抵抗、Coは等価容量、Loは等価インダクタンス
である。 First, the equivalent circuit of a zinc oxide thin film is shown in FIG. 9. In the figure, Cd indicates parallel capacitance, which is close to the capacitance when considering a zinc oxide thin film as a capacitor. Ro is series resonant resistance, Co is equivalent capacitance, and Lo is equivalent inductance.
Roは第１０図に示したインピーダンスと周波
数の関係から、直列共振周波数（o）に対応し、
このRoが大きくなれば発振に大きな増幅度が必
要となり、発振条件の低下をもたらすことになる
ことが伺える。 From the relationship between impedance and frequency shown in Figure 10, Ro corresponds to the series resonance frequency (o),
It can be seen that if this Ro becomes large, a large degree of amplification is required for oscillation, which leads to a decrease in the oscillation conditions.
第８図から明らかなように、この発明の実施例
によれば、従来例のAl電極のものにくらべRoの
経時変化が小さく、このことからこの発明にかか
る酸化亜鉛薄膜の電極構造は安定な電気的特性を
有するとともに、高温負荷寿命試験に対しても安
定した特性を示すものであると理解することがで
き、安定した発振を期侍することができるか否か
の目安となる。 As is clear from FIG. 8, according to the embodiment of the present invention, the change in Ro over time is smaller than that of the conventional Al electrode, and from this, the electrode structure of the zinc oxide thin film according to the present invention is stable. It can be understood that it not only has electrical characteristics but also exhibits stable characteristics even in high-temperature load life tests, and can be used as an indicator of whether stable oscillation can be expected.
以上この発明によれば、酸化亜鉛薄膜とAl電
極との間にAlの拡散防止層としてＶ層を介在さ
せたものであり、従来のものにくらべて実用上十
分な特性を示す酸化亜鉛薄膜を堤供することがで
きる。特にこの発明によれば、高温負荷寿命試験
に対してRoの変化が小さく、周波数変化が少な
いなど信頼性の高い酸化亜鉛薄膜が得られる。 As described above, according to the present invention, a V layer is interposed between the zinc oxide thin film and the Al electrode as a diffusion prevention layer of Al, and the zinc oxide thin film exhibits practically sufficient characteristics compared to conventional ones. You can donate. In particular, according to the present invention, a highly reliable zinc oxide thin film with small changes in Ro and small changes in frequency can be obtained in a high-temperature load life test.
第１図は音叉振動子の一例を示す側面図、第２
図は音叉振動子にこの発明にかかる酸化亜鉛薄膜
の電極構造を適用した例を示す側面図、第３図は
音片振動子にこの発明にかかる酸化亜鉛薄膜の電
極構造を適用した例の斜視図、第４図〜第６図は
同じくこの発明にかかる酸化亜鉛薄膜の電極構造
を各振動子に適用した例の側面図、第７図はこの
発明の具体的実施例にもとづく振動周波数の経時
変化特性図、第８図は同じくRoの経時変化特性
図、第９図は酸化亜鉛薄膜の等価回路図、第１０
図はインピーダンスと周波数の関係特性図であ
る。
１１……基板、１２……酸化亜鉛薄膜、１３…
…Ｖ層、１４……Al電極。
Figure 1 is a side view showing an example of a tuning fork vibrator;
The figure is a side view showing an example in which the zinc oxide thin film electrode structure according to the present invention is applied to a tuning fork vibrator, and FIG. 3 is a perspective view of an example in which the zinc oxide thin film electrode structure according to the present invention is applied to a tuning fork vibrator. 4 to 6 are side views of examples in which the zinc oxide thin film electrode structure according to the present invention is applied to each vibrator, and FIG. 7 is a graph showing the vibration frequency over time based on a specific embodiment of the present invention. Figure 8 is the change characteristic diagram of Ro over time, Figure 9 is the equivalent circuit diagram of zinc oxide thin film, Figure 10 is the change characteristic diagram.
The figure is a characteristic diagram showing the relationship between impedance and frequency. 11...Substrate, 12...Zinc oxide thin film, 13...
...V layer, 14...Al electrode.
Claims (1)
介在させたことを特徴とする酸化亜鉛薄膜の電極
構造。1. An electrode structure of a zinc oxide thin film, characterized in that a V layer is interposed between the surface of the zinc oxide thin film and an Al electrode.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11444882A JPS595723A (en) | 1982-06-30 | 1982-06-30 | Electrode structure of thin film of zinc oxide |
| US06/509,028 US4445066A (en) | 1982-06-30 | 1983-06-29 | Electrode structure for a zinc oxide thin film transducer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11444882A JPS595723A (en) | 1982-06-30 | 1982-06-30 | Electrode structure of thin film of zinc oxide |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS595723A JPS595723A (en) | 1984-01-12 |
| JPH0115208B2 true JPH0115208B2 (en) | 1989-03-16 |
Family
ID=14637982
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11444882A Granted JPS595723A (en) | 1982-06-30 | 1982-06-30 | Electrode structure of thin film of zinc oxide |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS595723A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62289124A (en) * | 1986-06-05 | 1987-12-16 | 溝田工業株式会社 | Plowland water level control apparatus by pressure reducing valve |
| JPS6342634A (en) * | 1986-08-06 | 1988-02-23 | 溝田工業株式会社 | Plowland water level controller by pressure reducing valve |
-
1982
- 1982-06-30 JP JP11444882A patent/JPS595723A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS595723A (en) | 1984-01-12 |
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